02-ten principles of economics ch1

PowerPoint® Lecture Presentationto accompany

Principles of Economics, Third EditionN. Gregory Mankiw

Prepared by Mark P. Karscig, Central Missouri State University.

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INTRODUCTION

Copyright © 2004 South-Western/Thomson Learning

11Ten Principles of Economics


TEN PRINCIPLES OF ECONOMICS

• A household and an economy face many decisions: • What goods and how many of them should be

produced?• How is it produced? What resources should be used

in production? Who will work?• Who gets what is produced and at what price should

the goods be sold?



• How people make decisions.• People face tradeoffs.• The cost of something is what you give up to get it.• Rational people think at the margin.• People respond to incentives.



• How people interact with each other.• Trade can make everyone better off.• Markets are usually a good way to organize

economic activity.• Governments can sometimes improve economic

outcomes.



• The forces and trends that affect how the economy as a whole works. • The standard of living depends on a country’s

production.• Prices rise when the government prints too much

money.• Society faces a short-run tradeoff between inflation

and unemployment.


Principle #1: People Face Tradeoffs.

“There is no such thing as a free lunch!”


Making decisions requires trading off one goal against another.

Principle #1: People Face Tradeoffs.

To get one thing, we usually have to give up another thing.

• Guns v. butter• Food v. clothing• Leisure time v. work• Efficiency v. equity


Principle #1: People Face Tradeoffs

• Efficiency v. Equality• Efficiency means society gets the most that it can

from its scarce resources.• Equality means the benefits of those resources are

distributed fairly among the members of society.


Principle #2: The Cost of Something Is What You Give Up to Get It.

• Decisions require comparing costs and benefits of alternatives.• Whether to go to college or to work?• Whether to study or go out on dinner?• Whether to go to class or sleep in?

• The opportunity cost of an item is what you give up to obtain that item.


Principle #2: The Cost of Something Is What You Give Up to Get It.

LA Laker basketball star Kobe Bryant chose to skip college and go straight from high school to the pros where he has earned millions of dollars.


People make decisions by comparing costs and benefits at the margin.

Principle #3: Rational People Think at the Margin.

• Marginal changes are small, incremental adjustments to an existing plan of action.


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3 Think at the Margin

Economists often consider how a small change in one variable affects another variable and what impact that has on people’s decision making.

• marginal changeA small, one-unit change in value.

When making a decision, one should only consider the additional (not total) cost or benefits that will arise from that decision.

Two important terms in this definition are,

Marginal Cost: Additional cost of producing one more unit of a good

Marginal Benefit: Additional benefit of producing one more unit of a good


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3 Think at the Margin

Example (1) : Suppose Mr. Z is flying to Honolulu to participate in a charity golf event (He has to pay for his own ticket to Hawaii). Suppose that after the charity event, he wants to spend a week in Maui. When making a decision whether or not to spend a week in Maui, what are the costs that Mr. Z should consider?

In this example, Mr. Z should only consider the additional cost of flying from Honolulu to Maui.

Example (2) : To drive home the point of marginalism, consider an example where you are taking a class that has 2 midterms and a final. After taking the two midterms your average was a 90. Suppose you wanted an A in the course. That would mean on the final exam you would need to score a 90 or above.

At this point in time, what really matters for your grade is not the two midterms, but rather the marginal grade (the grade on the final exam).


Principle #4: People Respond to Incentives.

• Marginal changes in costs or benefits motivate people to respond.

• The decision to choose one alternative over another occurs when that alternative’s marginal benefits exceed its marginal costs!


Principle #5: Trade Can Make Everyone Better Off.

• People gain from their ability to trade with one another.

• Competition results in gains from trading.

• Trade allows people to specialize in what they do best.


Principle #6: Markets Are Usually a Good Way to Organize Economic Activity.

• A market economy is an economy that allocates resources through the decentralized decisions of many firms and households as they interact in markets for goods and services.• Households decide what to buy and who to work

for.• Firms decide who to hire and what to produce.


Principle #6: Markets Are Usually a Good Way to Organize Economic Activity.

• Households and firms interacting in markets act as if guided by an “invisible hand.”• Because households and firms look at prices when

deciding what to buy and sell, they unknowingly take into account the social costs of their actions.

• As a result, prices guide decision makers to reach outcomes that tend to maximize the welfare of society as a whole.


Principle #7: Governments Can Sometimes Improve Market Outcomes.

• Market failure occurs when the market fails to allocate resources efficiently.

• When the market fails (breaks down) government can intervene to promote efficiency and equity.


Principle #7: Governments Can Sometimes Improve Market Outcomes.

• Market failure may be caused by • an externality, which is the impact of one person or

firm’s actions on the well-being of a bystander.• market power, which is the ability of a single

person or firm to unduly influence market prices.


Principle #8: The Standard of Living Depends on a Country’s Production.

• Standard of living may be measured in different ways:• By comparing personal incomes.• By comparing the total market value of a nation’s

production.



• Almost all variations in living standards are explained by differences in countries’ productivities.

• Productivity is the amount of goods and services produced from each hour of a worker’s time.



• Standard of living may be measured in different ways:• By comparing personal incomes.• By comparing the total market value of a nation’s

production.


Principle #9: Prices Rise When the Government Prints Too Much Money.

• Inflation is an increase in the overall level of prices in the economy.

• One cause of inflation is the growth in the quantity of money.

• When the government creates large quantities of money, the value of the money falls.


Principle #10: Society Faces a Short-run Tradeoff Between Inflation and Unemployment.• The Phillips Curve illustrates the tradeoff

between inflation and unemployment:

Inflation Unemployment

It’s a short-run tradeoff!

This has to do with the availability of resources. When unemployment is high there are lots of extra workers to produce more goods when demand increases, so more money chases more goods and hence no inflation. But when there is low unemployment it is harder to increase production and so there is upward pressure on prices.


Summary

• When individuals make decisions, they face tradeoffs among alternative goals.

• The cost of any action is measured in terms of foregone opportunities.

• Rational people make decisions by comparing marginal costs and marginal benefits.

• People change their behavior in response to the incentives they face.


Summary

• Trade can be mutually beneficial.

• Markets are usually a good way of coordinating trade among people.

• Government can potentially improve market outcomes if there is some market failure or if the market outcome is inequitable.


Summary

• Productivity is the ultimate source of living standards.

• Money growth is the ultimate source of inflation.

• Society faces a short-run tradeoff between inflation and unemployment.

02-ten principles of economics ch1

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